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Alcoholic beverage II

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Heat-treatment detrimental to juice and wine ... Control deleterious chemical reactions. Oxidation and browning. Microbial Ecology ... – PowerPoint PPT presentation

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Title: Alcoholic beverage II


1
Alcoholic beverage (II)
2
Wine Making
  • Sulfur Dioxide Treatment
  • Use wine starter cultures versus spontaneous
    (natural) fermentation
  • Inactivate indigenous microflora
  • Minimize competition and interference
  • Heat-treatment detrimental to juice and wine
  • Sulfite-treated, most commonly SO2 gas or
    potassium bisulfite
  • Inhibit wild yeast as well as acetic
    acid-producing microbes, malolactic bacteria, and
    various fungi
  • Control deleterious chemical reactions
  • Oxidation and browning

3
Microbial Ecology
  • Yeast primarily associated with grape surface
    Kloeckera apiculata
  • S. cerevisiae introduced into the must durng
    handling and crushing, most likely from the
    equipment
  • Succession
  • Must as selective environment
  • Low pH
  • Presence of organic acids
  • High sugar conc and high osmotic pressure
  • CO2 anaerobic, restrict growth of aerobic
    organisms
  • Ethanol
  • Sulfite

4
Microbial Ecology
  • Saccharomyces less than 10 of the initial yeast
    population
  • K. apiculata dominant
  • Produce 6 ethanol from glucose and fructose
  • Low ethanol tolerance, inhibited by 3-4 ethanol

5
Separation and Pressing
  • Juice separated from seeds, skins, and pulp
    (pomace) using screens by gravitational forces
  • 75 free run juice, more juice recovered by
    various processes (pressed juice)
  • Clarification
  • Settling, decantation, filtration or
    centrifugation

6
Fermentation
  • Limited fermentation before addition of starter
    culture
  • Culture added to the must
  • after pressing and clarification for white wine
    making
  • Before seed and skin removal for red wine (during
    maceration)
  • Traditional fermentation in open barrels, closed
    stainless steel tanks now more common

7
Fermentation
  • Temperature
  • 7-20C for white wine
  • 20-30C for red wine
  • Low temp loss less ethanol and volatile flavors
    due to evaporation
  • Produce more flavor compounds, ethanol and less
    sugar left
  • Wine fermentation generates heat, too much may
    affect wine fermentation (stuck)
  • Typically fermentation takes 3-5 days at 10-15C
  • Adjustments, blending, clarification
  • Aging

8
Malolactic Fermentation
  • As important as the yeast fermentation to wine
    quality
  • Acidity 3.3-3.6 for red wine, white wine slightly
    more acidic
  • High level organic acids, excess acidity serious
    flavor defect
  • Malic acid important to influence acidity
  • Decomposition into lactic acid via malolactic
    fermentation (fig 10-4)
  • Several LAB, particularly Oenococcus oeni
    (previously Leuconostoc), some Lactobacillus

9
Types of Wine
  • Sweet wines
  • noble rot by Botrytis cinerea
  • Dehydration of grapes
  • 9-13 ethanol, as much as 10 unfermented sugar
  • Fortified wines
  • Added distilled spirits (containing as much as
    95 ethanol) to raise ethanol conc to 15

10
Sparkling wines
  • Foam readily due to the presence of high
    concentration of dissolved CO2
  • 4.05-5.06 Pa (4-5 atm) at 20C (general), 2.03 Pa
    (2 atm) (US)
  • Methods of production
  • Champagne process (bottle fermentation, remove by
    disgorging)
  • Transfer profess (bottle fermentation, transfer
    to a tank, and removal of the yeast by
    filtration)
  • Bulk fermentation
  • Carbonation

11
Champagne Process
Dry white wine
Sucrose 25g/l, pure culture yeast
Secondary fermentation
9-12C, closed bottle Several months
Rest for months-years
Yeast is collected and frozen in the neck of the
bottles
Disgorge
Lost volume replaced by a sucrose solution
12
Other processes
  • Transfer process
  • Bottle fermentation
  • Yeast removed by transferring wine to a tank with
    nitrogen pressure
  • Add dosage, filtered and bottle filled with
    nitrogen or CO2 counterpressure
  • Bulk fermentation
  • Mass production, fermentation carried in
    pressured vessel
  • Filtration and bottling
  • Carbonation
  • No secondary fermentation

13
Vinegar
14
Vinegar
  • Can be make from almost any fruits, grains, mash
    (alcohol-containing), beer and wine
  • Contains at least 4 g of acetic acid per 100 ml
    (20C)
  • pH 2-3.5

15
Chemistry
Acetic acid
Sugar
Alcohol
Acetic acid
Lactic acid
Acidic acid bacteria Acetobacter Gluconobacter, G
luconoacetobacter, Acidomonas
Lactic acid bacteria, yeasts
16
Vinegar Fermentation
  • Oxidative fermentation, ethanol oxidized with air
    to acetic acid and water
  • By Acetobacter spp.

C2H5OH O2
CH3COOH H2O
17
Varieties
  • Wine vinegar
  • From grape wine
  • Cider vinegar
  • From apple cider
  • Malt vinegar
  • Barley malt or cereals, with starch converted by
    the malt
  • Rice vinegar
  • Saccharification of rice starch, followed by
    alcoholic and acetous fermentation
  • Sugar vinegar, whey vinegar, fruit vinegar, etc.

18
Nutrients and water requirements
  • Usually dont need additional nutrients
  • Ammonium phosphate sometimes is added to apple
    cider and some grape wines
  • Water free from chlorine
  • Additional nutrients required to make distilled
    vinegar

19
Behavior of Acetobacter in vinegar fermentation
  • Lack of oxygen
  • Significant cell damage 10-100, depend on the
    duration
  • Lack of ethanol
  • Cause sever damage to the cells
  • Changes in temperature
  • Temperature circulation too quick, cause cell
    damage
  • Over-oxidation
  • Undesirable oxidation to CO2
  • automation
  • Growth rate, etc.

20
Conditions for vinegar fermentation
  • Step 1 alcoholic fermentation
  • Organism(s) involved
  • Fermentation condition
  • Step 2 acetification
  • Organism(s) involved
  • Fermentation condition
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